A paste-like adhesive is mainly used as an adhesive for fixing a semiconductor element for joining between a semiconductor element and a support member such as a substrate. In recent years, downsizing of the support member to be used is also required with downsizing of semiconductor elements, and downsizing and improvement in performance of the semiconductor packages. For such a requirement, the paste-like adhesive paste-like adhesive unfortunately spreads, causing protrusion. Further, in the paste-like adhesive, it is difficult to control a thickness, and consequently, the semiconductor element is inclined to cause problems such as a defect of wire bonding. Therefore, joining using a conventional paste-like adhesive cannot adequately respond to recent semiconductor packages.
Further, in recent years, as described in Patent Document 1 described below, an adhesive sheet having a film-like adhesive layer has been used.
In a joining method using the adhesive sheet, the adhesive sheet (adhesive layer) is bonded to a back surface of a semiconductor wafer first, and a dicing sheet is bonded to the other surface of the adhesive layer. Thereafter, the semiconductor wafer is singulated with the adhesive layer bonded to the semiconductor wafer by dicing to obtain a semiconductor element. Next, the semiconductor element with the adhesive layer is picked up and joined to the support member. Thereafter, undergoing assembling steps such as wire bonding, sealing and the like, a semiconductor device is obtained.
However, in the production of a semiconductor device using the adhesive sheet, since the adhesive sheet clings to a cutting blade at the time of dicing to deteriorate a cutting property, there is a problem that the semiconductor chip chips, resulting in a reduction of a yield. Further, since a support member such as a substrate has a height difference of a wiring pattern, voids easily remain in the height difference portion. The void causes the reliability to deteriorate.
Further, Patent Document 2 discloses an adhesive containing a radiation-polymerizable compound, a photo initiator, and a thermosetting resin. However, in such an adhesive, there is a problem that with a substrate having a height difference of a wiring pattern, voids are generated to deteriorate reliability.
Patent Document 3 described below discloses an adhesive including (1) an epoxy resin, (2) a radically curable resin, (3) a photo-radical initiator, and (4) a latent epoxy curing agent. (4) The latent epoxy curing agent can be obtained by reacting (a) an amine compound represented by a specific formula (I), (b) a polyamine compound having two or more amino groups in a molecule, (c) an organic polyisocyanate compound, and (d) an epoxy compound. However, even if using such an adhesive, there is a problem that in a substrate having a height difference of a wiring pattern, voids are generated to deteriorate reliability.
Further, in conventional adhesives, adhesiveness after bonding may become low. Moreover, the conventional adhesives also have a problem of low reliability since the adhesiveness of the adhesive may become low when the adhesive is exposed to extreme conditions such as a high temperature or a high humidity.